1. Field of the Invention
This invention relates to surface active agents in the form of N and N,N hydroxyalkyl substituted higher organic amides.
2. Description of the Prior Art
The alkanolamides find extensive use in a variety of liquid detergent preparations wherein they primarily serve to promote or boost the foaming ability of the anionic surfactant component of the preparation as well as to stabilize the foam. Examples of such preparations include dishwashing liquids, shampoos, bubble bath formulations, light floor and wall cleaners, etc.
The alkanolamides are marketed in two grades for use in the aforesaid applications. One grade, referred to as a conventional Kritchevsky alkanolamides, encompasses those compositions containing about 65% alkanolamide and 35% of the corresponding alkanolamine. These products are prepared by reacting one mole of a fatty acid with two moles of the alkanolamine. The other grade, referred to as a superamide, contains in excess of 90% of the alkanolamide. Both grades are generally considered substantially equally effective for the purpose of foam promotion and stabilization. On the other hand, the respective types behave differently in physical characteristics in the various indicated formulations and consequently the choice between the two is usually predicated on the detergent formulator's particular requirement in this regard.
The superamides are customarily prepared by transesterifying the methyl ester of a detergent grade fatty acid with a primary or secondary alkanolamine, and generally the latter. The drawback associated with this manner of obtaining a superamide is that the reaction is difficult to complete to the extent whereby residual ester does not give rise to odor problems as well as adversely affecting the foam stabilization capabilities of the alkanolamide.